Potentially invasive exotic crustacean
found in Quebec
41 Cont’d
Potentially invasive exotic crustacean found in Quebec
Potentially invasive exotic crustacean found in Quebec
Chinese mitten crab Eriocheir sinensis Crabe chinois à mitaines
This species is native to the Yellow Sea, which is located between Korea and China.
It has been introduced in Europe, on the west coast of the United States and in the Great Lakes. It is found in Quebec in the St. Lawrence system. To date, the presence of at least eight specimens have been reported in the St. Lawrence River. It has probably been introduced through the release of ballast water.
D e s c r i p t i o n :
They are catadromous. They spend most of their life in freshwater, but they must return to the sea to breed. During their third, fourth or fifth year, before attaining sexual maturity, they migrate over distances of up to hundreds, even thousands, of kilometres to reproduce in salt water.
The main characteristic of this species is its dense patches of hair on its claws that resemble mittens. Claws have white tips.
The carapace is about 30 to 100 mm wide. It is convex and rough, and barely wider than long. It is light brown to olive-green in color, sometimes mottled.
Legs are longer and lighter in colour than the carapace. There is a notch on the carapace between the eyes.
Males and females die shortly after the breeding period.
Juvenile crabs spend some time in salt water before gradually moving upstream into freshwater, thus completing their life cycle.
It has an opportunistic diet which includes algae, detritus and a variety of aquatic invertebrates.
I m p a c t o f t h e i n t r o d u c t i o n :
They are considered as one of the 100 worst invasive alien species in the world.
Their presence in the St. Lawrence Estuary is a cause for concern as they can enjoy perfect conditions to reproduce. The tributaries of the river and estuary are also considered as risk-prone areas.
Since their population dramatically increases in areas where they are introduced, they could be a potential competitor for food with native species.
Credit: Guy Verreault (MRNF)
Chinese mitten crab
Juvenile crabs form dense colonies and create burrows in the intertidal portions of streams, a process which has undermined the integrity of stream banks in both Europe and the United States. The purpose of these burrows is to protect themselves from predators and desiccation which occurs during low-tide periods.
Tunnels are 12 to 20 cm in diameter and 20 to 80 cm deep. Their density can sometimes be significant – up to 30 burrows/m2.
They have excellent walking skills. They can travel over very long distances on earth.
The Chinese mitten crab is the secondary intermediate host for the Paragonimus westermaniparasite (Oriental lung fluke – similar to tuberculosis), with mammals, including humans, are the final host. Humans can become infested by eating this crustacean.
R e f e r e n c e s :
Anonymous. Chinese mitten crab. [On line]
[http://www.ag.ohio-state.edu/~exotic/nr615au01/metzler/webpage.html] (March 2007).
Deaheim, R., J. Goen and F. Wegelein, 1998. Chinese mitten crabs (Eriocheir sinensis) a threat to Washington State waters? [On line]
[http://www.seerecht.org/wegelein/course/group/crab1.htm] (March 2007).
Environment Canada. St. Lawrence Centre: Presence of the Chinese Mitten Crab in the St. Lawrence River [On line] [http://www.qc.ec.gc.ca/csl/inf/inf003_007_f.html]
(March 2007).
Global Invasive Species Database. Eriocheir sinensis(crustacean). [On line]
[http://www.issg.org/database/species/ecology.asp?fr=3&si=614&sts=] (March 2007).
Maryland Department of Natural Resources. Chinese Mitten Crab Watch. [On line]
[http://www.dnr.state.md.us/dnrnews/infocus/mitten_crab.asp] (February 2007).
Metzler, J.L. Chinese Mitten Crab (Eriocheir sinensis).
[On line] [http://www.iisgcp.org/EXOTICSP/Chinese_Mitten_Crab.htm] (February 2007).
Natural history museum. Chinese mitten crabs. [On line]
[http://www.nhm.ac.uk/nature-online/life/other-invertebrates/chinese-mitten-crabs/
chinese-mitten-crabs.html] (March 2007).
The Washington Post, August 8, 2006. Discovery of second invasive Mitten Crab raise worries. [On line] [http://www.washingtonpost.com/wpdyn/content/article/2006/08/07/
AR2006080701309.html] (March 2007).
Washington Sea Grant. Chinese Mitten Crab. [On line]
[http://www.wsg.washington.edu/outreach/mas/nis/mittencrab.html] (March 2007).
Wikipedia. Chinese mitten crab. [On line]
[http://www.dnr.state.md.us/dnrnews/infocus/mitten_crab.asp] (March 2007).
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Potentially invasive exotic crustacean found in Quebec Potentially invasive exotic crustacean
found in Quebec
Cont’d
Potentially invasive exotic crustacean found in Quebec
Potentially invasive exotic crustacean found in Quebec
Green crab Carcinus maenas Crabe vert
The Green crab's native range extends along the Atlantic coasts of Europe and northern Africa, from Norway to Mauritania. It has been introduced in the United States at the beginning of the 19thcentury. It has progressively established itself in other areas, especially from Maryland to northeast Maine, and would have reached southwest New-Brunswick in the 1950’s. Its presence was first reported in Quebec in 2004 in Îles de la Madeleine. During that period, 7 crabs were captured by an eel fisherman.
D e s c r i p t i o n :
They inhabit brackish and salt water.
Their trapeze-shaped carapace is larger than long (up to 85 cm wide and 65 cm long).
Despite its name, the colour of its carapace cannot be considered as a distinctive charac-teristic. It is variable, usually mottled, dark brown to dark green, granules for the most part yellow. The ventral surface of the adult crab may vary from green to yellow, orange and red.
Claws may be of various sizes.
The main distinctive characteristic of this species is that there are five large triangular spines (teeth) peripheral to its carapace on each side of its eyes.
There are three lobes (small tips) between both eyes. Moreover, the fourth pair of walking legs is somewhat flattened and pointed.
They are capable of withstanding a large range of temperatures and salinities, which allows them to easily adapt to new environments – temperatures from
0 to 33 oC and salinities from 4 to 54 ‰.
Credit: Guglielmo Tita Illustration : Paille et al. 2006
Green crab
They have the capacity to remain out of the water for ten days if the air is fresh and humid.
Adult females are typically smaller than adult males.
They inhabit all types of protected and semi-protected marine and estuarine habitats and they avoid turbulent areas.
During their larval stage, crabs feed on zooplankton, bacteria, phytoplankton and detritus. Once adult, they become voracious omnivores. They feed on a variety of organisms, including molluscs such as quahogs, clams, mussels, aquatic worms, fish, algae, and other small crustaceans (including other crab species).
I m p a c t o f t h e i n t r o d u c t i o n :
They are considered as one of the 100 worst invasive alien species in the world.
Due to their capacity to consume large amount of molluscs, they ravage mussel cultures.
They compete for food and habitat space with other native species. A study has shown that the Green crab and Rock crab are huge competitors. However, the Green crab is smaller, but more aggressive than the Rock crab.
Introduced non-native species may sometimes represent a disease vector.
Effectively, they may sometimes transmit parasites to certain populations of native species. For example, the Green crab may be the intermediate host of the Profilicollis botulusworm which causes many fatalities among common eider ducks.
Green crabs can have adverse impacts on eeling. Effectively, eels do not enter traps in which there are Green crabs.
In Europe, Green crabs are exploited as a food resource. They are also used as baits.
R e f e r e n c e s :
Global Invasive Species Database. Carcinus maenas. [On line]
[http://www.issg.org/database/species/ecology.asp?si=114&fr=1&sts] (March 2007).
Government of Prince Edward Island. Green crab. [On line]
[http://www.gov.pe.ca/af/agweb/index.php3?number=1015634&lang=E] (March 2007).
Paille, N., J. Lambert, N. Simard and S. Pereira. 2006. Le crabe vert (Carcinus maenas): revue de littérature et situation aux Îles-de-la-Madeleine. Rapp. Tech. Can. Sci. Halieut.
Aquat. 276 : vi +36 p.
USGS. Carcinus maenas.
[On line] [http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=190] (March 2007).
Potentially invasive exotic crustacean found in Quebec Potentially invasive exotic crustacean
found in Quebec
Cont’d
Potentially invasive exotic crustacean found in Quebec
Potentially invasive exotic crustacean found in Quebec
Rusty crayfish Orconectes rusticus Écrevisse à taches rouges
This species is native to Ohio, Kentucky and Tennessee. Spread by anglers who use them as bait, its presence was first reported in Quebec in 2001, in Lake Pemichangan and in the Ottawa River.
D e s c r i p t i o n : They occur in freshwater.
It is very hard to identify crayfish species; they somewhat all look alike. However, some distinctive characteristics allow identifying the Rusty crayfish.
Their carapace is in hues of bluish grey to brown or dark green.
Adult Rusty crayfish have large rust-coloured spots on each side of their carapace.
Their claws are more robust than that of some other crayfish species.
They inhabit lakes, ponds, and streams. They prefer areas that offer rocks, logs, or other debris as cover. Rusty crayfish inhabit both pools and fast water areas of streams.
They generally do not dig burrows other than small pockets under rocks and other debris.
They feed on a variety of aquatic plants, benthic invertebrates (like aquatic worms, snails, leeches, clams, aquatic insects, and crustaceans), detritus, fish eggs, and small fish.
I m p a c t o f t h e i n t r o d u c t i o n :
They are aggressive and frequently force native crayfish to relocate.
They reduce the amount and kinds of aquatic plants and invertebrates.
The destruction of aquatic plants caused by this species has resulted in the loss of breeding areas and habitats of several fish.
Credit: USGS
Rusty crayfish
R e f e r e n c e s :
Anonymous. Orconectes (Procericambarus) rusticus. [On line]
[http://www.ncwildlife.org/pg07_wildlifespeciescon/nccrayfishes/o_rusticus/o_rusticus.html]
(March 2007).
GLIN. Rusty Crayfish in the Great Lakes Region.
[On line] [http://www.great-lakes.net/envt/flora-fauna/invasive/rusty.html] (April 2007).
Global Invasive Species Database. Orconectes rusticus. [On line]
[http://www.issg.org/database/species/ecology.asp?si=217&fr=1&sts=] (March 2007).
Michigan.gov. Rusty crayfish (Orconectes rusticus). [On line]
[http://www.michigan.gov/dnr/0,1607,7-153-10370_12145_25065-33021—,00.html]
(March 2007).
Nature.ca. La nature du canal Rideau.
[On line] [http://nature.ca/rideau/b/b9b-f.html] (March 2007).
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